Battery pack and battery cooling system

Abstract

A battery pack includes plural cells each having a positive electrode terminal and a negative electrode terminal; plural battery modules in which the plural cells are laminated; a battery case in which the plural battery modules are accommodated; a water jacket disposed on the battery case or inside the battery case and configured to allow a first refrigerant to flow through the water jacket and perform heat exchange with the plural battery modules; a heat exchanger disposed on the battery case or inside the battery case and configured to allow a second refrigerant to flow through the heat exchanger and perform heat exchange with air inside the battery case; and a fan disposed on the battery case or inside the battery case and configured to allow air inside the battery case to circulate.

What is claimed is: 
     
         1 . A battery pack comprising:
 a plurality of cells each having a positive electrode terminal and a negative electrode terminal;   a plurality of battery modules in which the plurality of cells are laminated;   a battery case in which the plurality of battery modules are accommodated;   a water jacket disposed on the battery case or inside the battery case and configured to allow a first refrigerant to flow through the water jacket and perform heat exchange with the plurality of battery modules;   a heat exchanger disposed on the battery case or inside the battery case and configured to allow a second refrigerant to flow through the heat exchanger and perform heat exchange with air inside the battery case; and   a fan disposed on the battery case or inside the battery case and configured to allow air inside the battery case to circulate.   
     
     
         2 . The battery pack according to  claim 1 , wherein
 the water jacket cools the plurality of battery modules from below,   the battery case includes
 a first section in which the plurality of battery modules are disposed and heat exchange is performed between the plurality of battery modules and the water jacket, 
 second sections which are above the water jacket and in which the plurality of battery modules are not disposed, and 
 a gap which is provided between the plurality of cells and an inner wall of the battery case and configured to allow air to pass through the gap. 
   
     
     
         3 . The battery pack according to  claim 2 , wherein
 the battery case accommodates a junction box, and   the junction box is disposed such that air circulating through the first section and the second sections by the fan comes into contact with a conductive member of the junction box.   
     
     
         4 . The battery pack according to  claim 2 , wherein
 the second sections are positioned outside the first section and on both sides of the first section, and   the heat exchanger and the fan are disposed in the second sections.   
     
     
         5 . The battery pack according to  claim 4 , wherein
 the fan is disposed in each of the second sections,   the second sections each has
 a positive pressure region which is a side of the fan where air is discharged from the fan, and 
 a negative pressure region which is a side of the fan where the air is introduced into the fan, 
   the positive pressure region of the second section on one side and the negative pressure region of the second section on other side face each other with the first section interposed therebetween, and   the negative pressure region of the second section on the one side and the positive pressure region of the second section on the other side face each other with the first section interposed therebetween.   
     
     
         6 . The battery pack according to  claim 1 , wherein
 the plurality of battery modules include a terminal insulating cover that covers at least one cell terminal of the positive electrode terminals and the negative electrode terminals of the cells, and   a space extending in a lamination direction of the cells is provided between the terminal insulating cover and the cell terminal.   
     
     
         7 . The battery pack according to  claim 2 , wherein
 the second sections are positioned outside the first section and on both sides of the first section, and   an air path orthogonal to an extending direction of the second sections and connecting the second section on one side and the second section on other side is provided between the battery modules adjacent to each other, or between the battery modules and a cross member.   
     
     
         8 . A battery cooling system comprising:
 the battery pack according to  claim 1 ;   a refrigerant circuit configured to allow the first refrigerant flowing through the water jacket to circulate;   a heat pump circuit configured to allow the second refrigerant flowing through the heat exchanger to circulate;   a second heat exchanger configured to perform heat exchange between the first refrigerant and the second refrigerant; and   a controller configured to control the heat exchanger, the second heat exchanger, and the fan.   
     
     
         9 . The battery cooling system according to  claim 8 , wherein
 the controller
 controls the second heat exchanger to an ON state when a temperature of the cell is higher than a first threshold, and 
 controls the heat exchanger and the fan to an ON state when a terminal temperature of the cell is higher than a second threshold. 
   
     
     
         10 . The battery cooling system according to  claim 8 , wherein
 the heat pump circuit has, upstream of a flow path flowing to the second heat exchanger, a branch portion to the flow path flowing to the heat exchanger.